In general, a connecting rod is a mechanical element provided between a piston and a crank to convert reciprocating motion into rotary motion, and may include a big end connected to a crankshaft, a small end connected to a piston shaft, and a connection part for interconnecting the big and small ends.
The connecting rod mostly uses an iron-based alloy having excellent toughness and fatigue resistance against repeated explosions of the piston, and is manufactured using casting, forging, or sintered powder molding.
However, since the connecting rod manufactured using casting, forging, or sintered powder molding is not easily producible in a large quantity due to processing characteristics thereof, productivity is low, economic feasibility is low, and products are high-priced and heavy-weighted, and have a high defect rate due to structural detects, porosity defect, etc. thereof.
To solve the above problem, KR 2001-0097861 discloses a method of manufacturing a connecting rod using an extrusion die.
However, according to the connecting rod manufactured using the above conventional technology, a big end should be cut using a cutting device to interconnect a crankshaft and the big end. As such, manufacturing costs and manufacturing time of products are increased, productivity is lowered, and prices of the products are increased.